Inorganic crystal type electrooptical modulators are well known. Generally speaking, they operate in the following manner. Linearly polarized light is passed through a crystal medium exhibiting an electrooptical effect and the output beam is passed through another polarizer. A modulating electrical field is applied to control the eccentricity and orientation of elliptical polarization and hence the magnitude of the component of light in the direction of the output polarizer. Typically, the input linear polarization is oriented to have equal components along fast and slow axes of the crystal medium and the output polarizer is orthogonal to the input polarizer. The modulating field causes a phase differential varying from zero to .pi. rad. This causes the polarization to change from linear (at zero) to circular (at .pi./2) to linear normal to the input polarization (at .pi.). Thus the intensity passing through the output polarizer varies from zero to 100% as the phase differential varies from zero to .pi. rad. See for example the "Electronics Engineers Handbook", Second Edition, by Donald G. Fink and Donald Christianson, published in 1982 by McGraw-Hill Book Company (Library of Congress Catalog No. TK 7825.E34).
The medium that is typically used in optical modulators is an inorganic crystal material which is bulky, expensive and requires high voltage electrical fields to perform the modulating or switching function.
A principal object of the present invention is to provide an improved optical modulator which utilizes a polymer film medium which is small in size, is relatively inexpensive, and permits high speed modulation by use of very small applied immediate potential for information control in optical circuitry, laser modulation and deflection, and the like.